This invention relates to a solid three-piece golf ball having a long flying distance, a striking response substantially as good as that of a thread-wound golf ball, and an excellent capability of being controlled.
Golf balls which have generally been used include thread-wound golf balls and solid golf balls such as two-piece golf balls which are typical thereof. In recent years, solid two-piece golf balls have remarkably spread. This is mainly ascribed to excellent durability and flying distance characteristics of the ball. However, the compression (hardness) of the solid two-piece golf ball is generally higher than that of the thread-wound golf ball, and the striking response and the capability of being controlled of the former golf ball are therefore not satisfactorily good. Because of these facts, there is still deep-rooted popularity of thread-wound golf balls among higher-grade golfers including professional golfers.
It is considered that the high capability of being controlled of this kind of golf ball is ascribable to the moderate deformation thereof, which occurs when the ball is struck by a club. Namely, in a two-piece ball having a high compression, the degree of the deformation is low, so that this ball separates early from a club face when it is struck by the club. This makes it difficult to drive this ball in a carry-away stroke. On the other hand, a golf ball having too low a compression separate from a club face too late when it is struck by the club. Therefore, the ball is influenced largely by the characteristics of the club, and more difficult to control.
There is a method of solving these problems of solid two-piece golf balls, in which method the quantities of methacrylic acid and zinc oxide are reduced from a mixture for the core of a two-piece ball to soften the core as disclosed in Japanese patent application Kokai publication No. 60-163673. However, according to this method, the long flying distance constituting a characteristic of two-piece balls is sacrificed. Therefore, it is impossible to prevent this inconvenience, i.e., compensate for the decrease in the flying distance of this two-piece ball even if only the shell thereof has been improved.
More methods proposed for the same purpose are disclosed in Japanese patent application Kokai publication Nos. 51-49840 and 60-241464, which are directed to the manufacture of solid three-piece golf balls. However, neither of the golf balls disclosed in these publications has a striking response substantially as good as that of a thread-wound ball, a high capability of being controlled and a long flying distance which is the life of a golf ball.